Use any SMTP to send mail in Magento

This article will explain how to create an extension to send all the emails through gmail or other servers.I have created an module to set up an email account from admin.
I have made use of "Zend_Mail_Transport_Smtp" class to make it possible.

Create a directory structure:
app\code\local\Rajesh\MailTransport\Model\Core\Email
app\code\local\Rajesh\MailTransport\etc

Create the following files:
1.app\code\local\Rajesh\MailTransport\etc\config.xml.
<?xml version="1.0"?>
<config>
<modules>
<Rajesh_MailTransport>
<version>1.0.0</version>
</Rajesh_MailTransport>
</modules>
<global>
<models>
<core>
<rewrite> <email_template>Rajesh_MailTransport_Model_Core_Email_Template</email_template>
</rewrite>
</core>
</models>
</global>
</config>

2.app\code\local\Rajesh\MailTransport\etc\system.xml.
<?xml version="1.0"?>
<config>
<sections>
<system>
<groups>
<rajesh_mail_transport module="core">
<label>Rajesh | MailTransport</label>
<frontend_type>text</frontend_type>
<sort_order>15</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
<comment>Overrides Magento's default email "send" method from within the Mage_Core_Model_Email_Template class. Allows you to use any email server that supports SMTP to send emails in place of built in email server on your web host.</comment>
<fields>
<auth translate="label">
<label>Authentication method</label>
<frontend_type>select</frontend_type>
<source_model>adminhtml/system_config_source_email_smtpauth</source_model>
<sort_order>40</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
<comment>Use "login" for Gmail.</comment>
</auth>
<ssl translate="label">
<label>SSL type</label>
<frontend_type>text</frontend_type>
<sort_order>41</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
<comment>Use "tls" for Gmail.</comment>
</ssl>
<smtphost translate="label">
<label>SMTP host</label>
<frontend_type>text</frontend_type>
<sort_order>42</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
<comment>Use "smtp.gmail.com" for Gmail.</comment>
</smtphost>
<username translate="label">
<label>Username</label>
<frontend_type>text</frontend_type>
<sort_order>43</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</username>
<password translate="label">
<label>Password</label>
<frontend_type>password</frontend_type>
<sort_order>44</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</password>
</fields>
</rajesh_mail_transport>
</groups>
</system>
</sections>
</config>

3.app\code\local\Rajesh\MailTransport\Model\Core\Email\Template.php
<?php
class Rajesh_MailTransport_Model_Core_Email_Template extends Mage_Core_Model_Email_Template {
const MODULE_SETTINGS_PATH = 'rajesh_mail_transport';

public function send($email, $name = null, array $variables = array()) {
if (!$this->isValidForSend()) {
Mage::logException(new Exception('This letter cannot be sent.')); // translation is intentionally omitted
return false;
}
if (is_null($name)) {
$name = substr($email, 0, strpos($email, '@'));
}
$variables['email'] = $email;
$variables['name'] = $name;
ini_set('SMTP', Mage::getStoreConfig('system/smtp/host'));
ini_set('smtp_port', Mage::getStoreConfig('system/smtp/port'));

$mail = $this->getMail();
$setReturnPath = Mage::getStoreConfig(self::XML_PATH_SENDING_SET_RETURN_PATH);
switch ($setReturnPath) {
case 1:
$returnPathEmail = $this->getSenderEmail();
break;
case 2:
$returnPathEmail = Mage::getStoreConfig(self::XML_PATH_SENDING_RETURN_PATH_EMAIL);
break;
default:
$returnPathEmail = null;
break;
}
if ($returnPathEmail !== null) {
$mail->setReturnPath($returnPathEmail);
}
if (is_array($email)) {
foreach ($email as $emailOne) {
$mail->addTo($emailOne, $name);
}
} else {
$mail->addTo($email, '=?utf-8?B?'.base64_encode($name).'?=');
}
$this->setUseAbsoluteLinks(true);
$text = $this->getProcessedTemplate($variables, true);
if($this->isPlain()) {
$mail->setBodyText($text);
} else {
$mail->setBodyHTML($text);
}
$mail->setSubject('=?utf-8?B?'.base64_encode($this->getProcessedTemplateSubject($variables)).'?=');
$mail->setFrom($this->getSenderEmail(), $this->getSenderName());

try {
$systemStoreConfig = Mage::getStoreConfig('system');
$emailSmtpConf = array(
//'auth' => 'login',
'auth' => strtolower($systemStoreConfig[self::MODULE_SETTINGS_PATH]['auth']),
//'ssl' => 'tls',
'ssl' => strtolower($systemStoreConfig[self::MODULE_SETTINGS_PATH]['ssl']),
'username' => $systemStoreConfig[self::MODULE_SETTINGS_PATH]['username'],
'password' => $systemStoreConfig[self::MODULE_SETTINGS_PATH]['password']
);
$smtp = 'smtp.gmail.com';

if($systemStoreConfig[self::MODULE_SETTINGS_PATH]['smtphost']) {
$smtp = strtolower($systemStoreConfig[self::MODULE_SETTINGS_PATH]['smtphost']);
}
$transport = new Zend_Mail_Transport_Smtp($smtp, $emailSmtpConf);
$mail->send($transport);
$this->_mail = null;
}
catch (Exception $ex) {
//Zend_Debug::dump($systemStoreConfig[self::MODULE_SETTINGS_PATH]);
//Zend_Debug::dump($ex->getMessage()); exit;
try {
$mail->send(); /* Try regular email send if the one with $transport fails */
$this->_mail = null;
}
catch (Exception $ex) {
$this->_mail = null;

//Zend_Debug::dump($systemStoreConfig[self::MODULE_SETTINGS_PATH]);
//Zend_Debug::dump($ex->getMessage()); exit;

Mage::logException($ex);
return false;
}
Mage::logException($ex);
return false;
}
return true;
}
}